A data search system that extracts desired data from a database has been used in various fields. As a format of the database, there is a RDB (Relational Database) in which attribute values of a plurality of columns are associated with each other.
For example, there is a system that extracts desired data from trace information indicating an execution result of a program, in which a type of functions (scopes) constituting a program, a start time at which processing of the function has been started, a processing time during which the processing of the function has been continued, and a calling relation between the functions are designated as columns, and data within a predetermined time range is extracted from the RDB sorted in chronological order based on the start time.
In the search system using the RDB described above, when a search condition corresponding to a column serving as a reference for sorting (a reference column) is specified, processing to extract data matching the search condition can be easily performed. For example, when a plurality of records constituting the RDB are sorted in chronological order and a certain time range is specified as the search condition, records included in the time range can be easily extracted.
However, if the search condition does not correspond to the reference column (for example, a search condition other than the time is specified in the database sorted in chronological order), it may be necessary to scan the entire database. When big data is specified as a search object, improvement of search efficiency is very important.